Phenylalanine Controls Blackberry Growth in Sustainable Soilless Culture and Enhances the Content of Phenolic Compounds

The study was conducted at Research Station A in the Coll. of Agri.Engi. Sci., U. of Baghdad during the 2022-2023, aiming to improve the vegetative growth and phenolic concentration in blackberry leaves by growing the plants in organic substrate soilless culture systems including licorice root residues (C 3 ) and cocopeat (C 2 ) compared to field soil (C1), as well as spraying the plants with phenylalanine (A) at three concentrations (0, 100, 200 mg.L -1 ). The results showed the superiority of the plants growen in cocopeat sprayed with 200 mg.L -1 of phenylalanine (C 2 A 2 ) exhibiting the highest N%, P%, plant height, leaves number, total leaf area, increase in protein%, chlorophyll, and total flavonoids in the leaves, while(C 3 A 2 ) was superior, in leaves beta-carotene and total phenols.